1. Field of the Invention
The present invention relates to a strobe flashing device used in a camera or the like, and more precisely, to a strobe flashing device having an increased light gathering (condensing) efficiency.
2. Description of Related Art
A strobe flashing device usually has a cylindrical stroboscopic tube which emits light towards an object to be taken through a reflector and a condenser lens. A spherical lens or a Fresnel lens, optically equivalent thereto, has been used as a condenser lens.
However, the spherical condenser lens has a reduced light condensing (gathering, or collecting) efficiency, in view of a cylindrical stroboscopic light emitting tube. Namely, since the light emission distribution of the stroboscopic light emitting tube in the longitudinal direction thereof is considerably different from that in the lateral direction perpendicular to the longitudinal direction and since the reflection shade has a semi-circular cross-section or semi-elliptical shape, if light emitted from the cylindrical stroboscopic light emitting tube is received by the spherical condenser lens which has uniform gathering characteristics in all directions with respect to the light axis, the amount of light which is not made incident upon the object is increased. Furthermore, in view of the distribution of light, there is a large difference in the incident angle of the light when the light emitted from the stroboscopic light emitting tube is directly incident upon the condenser lens and when the light emitted from the stroboscopic light emitting tube is first reflected by the reflection shade and is then made incident upon the condenser lens. Under these circumstances, it is next to impossible for the simple spherical lens to affectively condense light beams.